Link between dog food, Salmonella cases looks stronger

Aug 29, 2007 (CIDRAP News) Further investigation has strengthened the evidence of a link between recently recalled dog food products and human Salmonella infections, US health officials reported yesterday.

Sixty-six people in 18 states have been infected with the same strain of Salmonella Schwarzengrund, and reports of new cases are continuing, the Centers for Disease Control and Prevention (CDC) said in a statement.

The Food and Drug Administration had said earlier that two samples of dry dog food made by Mars Petcare US, Inc., had tested positive for S Schwarzengrund, but no direct link between the company's products and the human cases had been found.

The CDC, however, said yesterday that the outbreak strain of S Schwarzengrund was found in fecal specimens from two dogs that ate dry pet food in the homes of two case-patients. In addition, a multistate case-control study showed a link between illness and the purchase of dry pet foods made by Mars Petcare, the agency said.

"Households with ill persons were significantly more likely than matched households without ill persons to usually purchase a brand of dry pet food made by Mars Petcare US that may have been produced at a single facility in Pennsylvania," the CDC said.

In addition, the Pennsylvania Department of Health found the outbreak strain in an environmental sample from the Mars Petcare facility in Pennsylvania, the statement said.

The CDC said 25 of the 66 salmonellosis cases reported so far occurred in Pennsylvania, with 12 in New York, 6 in Ohio, 5 in Massachusetts, and 1 or 2 in each of the other states affected.

Of the patients for whom information was available, 39% were 1 year old or younger and 32% experienced bloody diarrhea. Ten patients were hospitalized, but none died, the CDC reported.

The agency said investigators are still trying to find out why human cases have been associated with dry pet food. Factors being considered include handling and storage of dry pet food, handwashing practices, exposure of children to dry pet food, and the location in the home where pets are fed.